The expression "nanofluid" refers to the suspended nanoparticles that maximize the combined heat and mass transfer phenomena within a typical fluid. Nanoparticles have fascinated the researchers’ interest in today’s modern era due to their significant importance in the fields of electronics, food science, biosensors, biomedicine, and mechanical engineering. Additionally, the movement of respective nanoparticles in designated structures is strongly dependent on the elementary concepts of cancer treatment, selective drug delivery, chemotherapy, fermentation science, and nanomedicine.

The dispersion of two or more materials in the same base fluid is known as hybrid nanofluids. These fluids have many applications in the field of medical sciences and engineering. Most of the drugs are prepared in the form of hybrid nanofluids and blood is used as a testing base fluid to check the chemical reactions of the materials in the blood. The hybrid nanofluids are also used to enhance the thermal efficiency of the base liquids. The nanomaterials configurations are selected to incorporate the beneficial effects including both nanomaterials into a single stable homogeneous system. Recently, hybrid nanofluids are mainly used in medicine for the treatment of various diseases like cancer therapy. For better blood circulation, a normal viscosity and normal temperature are required to sustain the regularity in the transmission of blood. Fractional calculus characterizes a function at those points, where classical calculus failed. Recently, the above-mentioned topics are the hot issues among researchers and most of the researchers are involved in the above-mentioned areas. Application areas of hybrid nanofluids are varied widely in almost all fields of heat transfer such as electronic cooling, engine cooling/vehicle thermal management, generator cooling, coolant in machining, welding, nuclear system cooling, lubrication, thermal storage, solar heating, cooling and heating in buildings, transformer cooling, biomedical, drug reduction, heat pipe, refrigeration, defence, space aircrafts and ships. Hybrid nanofluid applications in the industry have better efficiency than general nanofluids. Fractional Calculus (FC) originates from the theory of differential calculus.

Nevertheless, the application of FC just emerged in the last two decades, due to the progress in chaos that revealed subtle relationships with the FC concepts. In the field of dynamical systems theory, some work has been carried out, but the proposed models and algorithms are still in a preliminary stage of establishment. In recent years, FC has been a fruitful field of research in science and engineering. , many scientific areas are currently paying attention to the FC concept, and we can refer its adoption in viscoelasticity and damping, diffusion and wave propagation, electromagnetism, chaos and fractals, heat transfer, biology, electronics, signal processing, robotics, system identification, traffic systems, genetic algorithms, percolation, modelling and identification, telecommunications, chemistry, irreversibility, physics, control systems as well as economy, and finance.

This Special Issue aims to improve our current knowledge of nanofluids, hybrid nanofluids, biofluids. We especially welcome original research and review articles discussing current and potential applications. Submissions should cover analytical, computational, experimental, theoretical, classical, or fractional models.

Potential topics include but are not limited to the following:

• Hybrid nanofluids and biofluids
• Theoretical and experimental analysis of hybrid nanofluids
• Fractional calculus in hybrid nanofluids
• Shape and size of the nanoparticles
• Hybrid nanofluids in a solar collector
• Hybrid nanofluids in heat exchanger
• Hybrid nanofluids in medication
• Thermophysical properties of the nanofluids